Tree species exceeding 70m in height are rare globally. Giant gymnosperms are concentrated near the Pacific coast of the USA, while the tallest angiosperms are eucalypts (Eucalyptus spp.) in southern and eastern Australia. Giant eucalypts co-occur with rain-forest trees in eastern Australia, creating unique vegetation communities comprising fire-dependent trees above fireintolerant rain-forest. However, giant eucalypts can also tower over shrubby understoreys (e.g. in Western Australia). The local abundance of giant eucalypts is controlled by interactions between fire activity and landscape setting. Giant eucalypts have features that increase flammability (e.g. oil-rich foliage and open crowns) relative to other rain-forest trees but it is debatable if these features are adaptations. Probable drivers of eucalypt gigantism are intense intra-specific competition following severe fires, and inter-specific competition among adult trees. However, we suggest that this was made possible by a general capacity of eucalypts for ‘hyper-emergence’. We argue that, because giant eucalypts occur in rain-forest climates and share traits with rain-forest pioneers, they should be regarded as long-lived rain-forest pioneers, albeit with a particular dependence on fire for regeneration. These unique ecosystems are of high conservation value, following substantial clearing and logging over 150 yr.

Item Type:	Refereed Article
Keywords:	eucalyptus, forests, rain forest
Research Division:	Environmental Sciences
Research Group:	Ecological applications
Research Field:	Landscape ecology
Objective Division:	Environmental Management
Objective Group:	Terrestrial systems and management
Objective Field:	Terrestrial biodiversity
UTAS Author:	Tng, DYP (Mr David Tng)
UTAS Author:	Williamson, GJ (Dr Grant Williamson)
UTAS Author:	Jordan, GJ (Professor Greg Jordan)
UTAS Author:	Bowman, DMJS (Professor David Bowman)
ID Code:	82376
Year Published:	2012
Web of Science® Times Cited:	69
Deposited By:	Plant Science
Deposited On:	2013-01-29
Last Modified:	2017-01-24
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